He said: “The jobs there are priceless in the Neath Valley. They are well paid and highly skilled.

“They are exactly the sort of jobs we need.”

Aberpergwm opened in the late 19th century, and at its height during the 1930s employed more than 1,500 workers.

It closed in 1985 and reopened a year later under private ownership.

A spokesman for Walter Energy said: “This proposal is as a result of a challenging economic environment which continues to heavily impact the global coal industry.

“During this period of consultation, most of the employees will remain at home on full pay.

“However up to 100 employees may be required to continue working at the mine during this consultation period to continue development works within the upper drift.

“If Walter Energy proceeds with the proposals as outlined, early indications are that only a small number of employees would be retained to keep the mine in a safe condition until operations resume.

“Formal consultation will take place shortly with employee and trade union representatives and as such, it is inappropriate for the company to make any further comment at this time.”

Walter Energy, with its corporate and US headquarters in Birmingham, Alabama and its Canadian and UK headquarters in Vancouver, is the world’s leading publicly-traded coal producer for the global steel industry.

The company also produces steam coal and industrial coal, anthracite, metallurgical coke, and coal-bed methane gas, and employs about 4,400 employees and contractors overall.

Peter Hain said of the company’s announcement: “This is desperately disappointing.

“I have given the mine every support I can but it appears to be a victim of international factors including the global recession which is severely affecting the price of coal and the damaging policies by the Westminster government which are hitting businesses hard.

“To risk losing these highly-skilled and well-paid jobs would be a real body blow to our local communities.

“I hope that commercial conditions will improve so that the mine can start working again as it’s been so successful for the last ten years.

“I will continue to work with Rhidian Davies (managing director of the pit) and his team to secure the future.”

Aberpergwm is believed to have coal reserves of about 6.8m tonnes.

Its main customer is the Aberthaw power station in the Vale of Glamorgan, which buys around 1m tonnes of Welsh coal a year.

It has also supplied coal to Tata steel in Port Talbot.

RWE npower, which runs the coal-fired power station at Aberthaw, said the mine had been supplying it with coal for “many years” and it hoped its issues could be resolved.

A Welsh government spokesperson said it was “disappointed” with the suspension of operations at Aberpergwm.

The spokesman added: “Walter Energy’s announcement will come as a blow to the workers, their families and the local community.”